"Memory" not the only issue with Palm OS PDAs

[lmcjipo]

I just discovered something with my friend's Palm TX. Even though it has a lot of onboard memory, it is still possible that it can't run some programs.

While trying to launch a program, an error window pops up where the title of the window is "Free DB Cache Memory Too Small" and the actual message in this window is "Not enough free DB Cache Memory to run this application".

The only way that I discovered of solving this problem was to perform a soft reset on the TX.

I've never had this issue on my Treo 650 which has even less onboard memory than my friend's TX but of course except for some applications, we don't have the same programs installed on our PDAs. I even have less available memory than he has on his TX.

I guess that even though a PalmOS PDA has more onboard memory than another PalmOS PDA, the onboard memory is not the only thing to look at.

Anyone have any ideas about the PalmOS's error message and what DB Cache Memory is and how to increase it (or fix the problem without soft resetting the device)?

 

[lmcjipo]

I think that the program using a lot of DB Cache memory is CJKOS. My friend toggled it off and the error does not appear when she tries to use her GPS software.

Looking through Google, some of the documents that I found suggested downloading a DB Cache memory clearing program (such as Reset Doctor) but toggling CJKOS on when it is needed and off when it is not currently being used seems to have solved my friend's problem with her TX.

 

[mikelove]

DBCache is a new thing on Palms running Palm OS 5.4 or later, i.e. the models that use the new NVFS flash-memory-based file system. Basically, since programs on Palm OS are designed to work with RAM-based files, whenever a program wants to read a chunk of data stored in internal memory the OS loads that record into DBCache. If a program loads a lot of data at the same time (like CJKOS with its myriad fonts/phrase files/etc) and doesn't manage its memory properly, the DBCache can pretty easily run out.

I don't believe there's any way to increase this cache, RAM usage on OS5.4 Palms is pretty strictly specified by the OS and any RAM not being used for DBCache is used for some other essential purpose like application heap memory or the operating system's own use. It seems to be a pretty consistent 10 MB on just about all OS 5.4 models. So about the only workaround is to try to run as few background programs (like CJKOS, AeroPlayer, etc) as possible in order to maximize the amount of cache available to the foreground application. (PlecoDict, for what it's worth, will generally be happy as long as it has 3 MB or so of that cache free, though it'll run a lot faster with 4-5 since it won't have to reload data from the memory card as often)

 

[sui.generis]

While trying to launch a program, an error window pops up where the title of the window is "Free DB Cache Memory Too Small" and the actual message in this window is "Not enough free DB Cache Memory to run this application".

Glad to hear the toggling worked. The simplest solutions are always best. For anyone else, there are a number of cache clearing programs that automate the process, so you don't have to soft reset all the time. Uncache by dmitry (palmpowerups.com) for instance. I haven't used these programs, but heavy blazer users find them helpful. One should research a particular app well before using it, as some issues have been reported with some of them.

I don't believe there's any way to increase this cache,

True, though in the hack department there is Dmitry's UDMH which allows unfragmented portions of the nvfs partition to be used as heap memory. It's req'd fare for most emulation on the TX and helpful when using programs that handle large databases (gps, for instance). In the alternative, using a smaller custom rom would increase the dbcache portion of the TX, but not the heap.

The TX got pretty jipped in the ram department. A lot of T3 users are still waiting for a decent Palm to replace their units because of the memory limitations as well as the slower nvfs system, and lack of some bells and whistles. Had I been more aware of the technical limitations when I got mine, I might have bought a T3 off ebay instead.